Accidental Administrator Cisco ASA Security Appliance A Step-by-Step Configuration Guidel
Security levels are numeric values, ranging from 0 to 100, used by the appliance to control traffic flow. Traffic is permitted to flow from interfaces with higher security levels to interfaces with lower security levels, but not the other way. Access-lists must be used to permit traffic to flow from lower security levels to higher security levels. The default security level for an outside interface is 0. For an inside interface, the default security level is 100. In the following sample configuration, the interface command is first used to name the inside and outside VLAN interfaces, then the DMZ interface is named and a security level of 50 is assigned to it. interface vlan1 nameif inside interface vlan2 nameif outside interface vlan3 nameif dmz security-level 50
Accidental Administrator Cisco ASA Security Appliance A Step-by-Step Configuration Guidel